The present invention relates to a wireless communication medium for use in wireless communication, more specifically, a radio-frequency identification medium (RFID medium) generally called an IC tag. More particularly, the present invention relates to techniques effectively applicable to a RFID medium that is intended for use in combination with a thin or flexible structure, and to a method of manufacture of such a RFID medium.
The inventors of the present invention have found through studies that a RFID medium facilitates commodity management for inventory and commodity distribution, and authentication of commodities. The RFID medium has become prevalently used in combination with commodities for its inherent advantages. The RFID medium includes an IC chip for data processing and storage, and an antenna for signal transmission and reception. The RFID medium is shaped according to its intended usages in the form of a card or a sheet.
Usually a method of manufacturing a RFID medium uses a hot-pressing method or a lamination method. FIGS. 16(a) and 16(b) are sectional views of a RFID medium being formed by a general hot-pressing method. As shown in FIG. 16(a), a module 102, which is formed by joining an IC chip 100 and an antenna 101, is held between a base sheet 103 and a covering sheet 104 to form a structure. The structure is placed on a press 105, and the structure is compressed between a heated upper plate 106 and a heated lower plate 107 to form a semifinished RFID medium by bonding the base sheet 103 and the covering sheet 104 together. Then, the semifinished RFID, medium is shaped to obtain a RFID medium as shown in FIG. 16(b).
There are many lamination methods, including those disclosed in the below-listed Patent Documents 1 and 2.
A lamination method mentioned in Patent Document 1 will be described with reference to FIGS. 17 to 20. FIG. 17 shows an arrangement of component parts; FIG. 18 is a view illustrating a process of forming recesses in a base sheet; FIG. 19 shows an assembly of the base sheet and a cover sheet placed on the base sheet; and FIG. 20 is a sectional view of a finished, individual product.
As shown in FIG. 17, the lamination method mentioned in Patent document 1 forms hollows 113 in a base sheet 110; places modules 102, each formed by combining an IC chip 100 and an antenna 101, in the hollows 113; and laminates a covering sheet 104 to the base sheet 110 to protect the modules 102.
The hollows 113 are formed in the base sheet 110 by passing the base sheet 110 between two rotating rollers 111 and 112, as shown in FIG. 18. The roller 111 has an embossed circumference with a shape complementary to the shape of the hollow 113. The rollers 111 and 112 are heated to a temperature substantially equal to the softening point of the base sheet 110, so that the hollows 113 may be easily formed.
After the modules 102 have been placed in the hollows 113 of the base sheet 110, the covering sheet 104 is laminated to the base sheet by a hot-pressing method, a lamination method or an ultrasonic bonding method to form a laminated sheet having the modules 102, as shown in FIG. 19. The laminated sheet is cut into individual finished products, each including one module 102, as shown in FIG. 20.
A method mentioned in Patent Document 2 will be described with reference to FIGS. 21 to 23. FIG. 21 is a diagram illustrating a method of manufacturing an IC-inlaid band and an IC tag; FIG. 22 is a sectional view showing separate IC tag bodies; and FIG. 23 is a sectional view of IC tags formed by attaching labels to the IC tag bodies, respectively.
Referring to FIG. 21, which illustrates the method of manufacturing an IC-inlaid band and an IC tag, an IC-inlaid band a is wound around a roller A, a release sheet b is wound around a roller B, and a combined sheet formed by attaching the IC-inlaid band to the release sheet b is taken up on a roller C. The IC-inlaid band a unwound from the roller A is bonded to the release sheet b by rollers 201 and 202 to form the combined sheet, and the combined sheet is taken up on the roller C. An adhesive 204 is applied to the release sheet b using an application roller 200 before the release sheet b is bonded to the IC-inlaid band a. The combined sheet is cut with a cutting blade 203, which is disposed between the rollers 201, 202 and the roller C, such that the release sheet b is not cut and IC-inlaid parts are separated. An unnecessary part is taken up on a roller D.
In a state after the combined sheet has been thus cut, a release sheet 205 consists of a base sheet and a silicone resin layer 210, and IC inlays 208, each consisting of an IC chip 207 and an antenna, not shown, are separately arranged on the release sheet 205 with gaps 209 formed between the adjacent IC inlays 208, as shown in FIG. 22. Then, labels 211 are attached to the IC inlays 208, as shown in FIG. 23. The roller C is used in a process similar to that shown in FIG. 21 to increase the width of the gaps 209 on the release sheet according to the size of the labels 211.
[Patent Document 1] Japanese Patent Laid-open No. 2003-67696
[Patent Document 2] Japanese Patent Laid-open No. 2002-187223